1. Field of the Invention
The present invention relates to a method and system for replacing a lighting system in an existing microplate reader with a new light source. Specifically, the present invention relates to a system which can be used to replace a water cooled laser with an LED light system in an existing microplate reader.
2. Description of Related Art
The use of fluorescence analytical monitoring techniques is well known. Fluorescence measurements can be taken by shining a light source of a first wavelength and then when the sample of light is absorbed, the test material is induced to emit light of a second wavelength. Measurement of the second wavelength light, either as length, intensity or the like, can be used to correlate the activity in a cell that is producing the secondary fluorescence. Physiological parameters can then be determined based on the results, such as potassium or other ion channel activity. Florescence type measurements are of great importance to the research and development of new pharmaceutical compositions and are used to screen a variety of tissues for interaction with most any chemical composition that is of interest in affecting the measurable systems.
Typically, in the analysis of cells, a variety of older machines are available for using this type of technique with 96 or 384 well multiple well plates. These machines provide a multiwall plate holder, a water cooled laser light source and some form of a receiving camera for detecting the cell's second wavelength light emissions. The cells are cultured in each of the wells at the bottom with a growth medium provided over the growing cells. The chemical compound to be tested or otherwise assayed is played into the liquid in each well with the florescent material and the effect measured by excitation by the laser and reading by the camera. For example, in U.S. Pat. No. 5,355,215 to Schroder et al issued Oct. 11, 1994, there is disclosed a method for aligning a camera and a light source for measuring the second wavelength with a minimum about if interference from the supernate liquid. This process has been utilized extensively and appears in later machines and in more recently issued patents, for example, in U.S. Pat. No. 7,265,829 issued Sep. 4, 2007 to Jiang et al.
The older microplate reader machines that utilize water cooled lasers, while difficult to use, were well built and very cost effective. Such machines include the Flipr2® and Flipr3® microplate readers. These machines suffered from the difficulty of using and operating water cooled lasers but because parts were relatively accessible for repair, a burgeoning business in repair and refurbishment developed to keep these machines in service. Since the refurbishment of even a patented product is allowable repair, such repair has been accomplished not only by OEMs, but a variety of small companies also repair these types of machines. The lasers in these machines are typically in the 3 watt water cooled argon laser with power designed to be sufficient in order to provide sufficient light to produce excitation of each well in a microplate.
Newer microplate reader machines are very costly and tend to be large in an attempt to avoid the difficulties in using water cooled lasers. An example is the Fliprtetra® made by the same company as the older Flipr2 and Flipr3 machines, Molecular Devices (MDC). In order to encourage purchases of newer models of microplate readers, MDC has declined to support its older machines and encourage users of the older machines to upgrade. However, for many users the older machines are fine and there is a desire in the marketplace to continue refurbishing these machines. The fact that water cooled lasers that these machine were built to utilize are expensive, hard to use and getting scarce to fit the existing machines, has suggested the repair life of these machines is limited in spite of the desire of users to continue using the machines to the end of their useful life.
Digital lasers are now well known and can be obtained in a variety of wattages. However, the wattages of the air cooled laser types has not yet reached the 3 watts that are currently employed and rated for the existing machines with water cooled lasers. In fact, currently the largest air cooled lasers are in the 500 mW range and industrially considered not powerful enough to be used in a microplate reader.